Stiff nut



June 24,1947. V R. D. KING ETAL 2,422,833

STIFF uu'j:

Filed May 30, 1944 7RD Kin; and IVE Wood Patented June 24, 1947 ants OFFICE STIFF NUT Ronald D. King and Norman 1*. Wood, Portsmouth, England Application May 30, 1944, Serial No. 537,988 In Great Britain May 1'7, 1943 Section 1, Public Law 690, August 8, 1946. Patent expires May 17, 1963 1 Claim.

This invention relates to stiff nuts or nuts which grip tightly on the bolt and are in no danger of coming loose accidentally. The object of the invention is the provision of improvements in nuts of this kind, and, in accordance with the invention, a nut has mounted at one end a separately formed plate attachment having one or more openings through which the bolt passes and whereby a friction drag on said bolt is provided.

In order that the invention may be the more clearly understood a number of nut constructions in accordance therewith will now be described, reference being made to the accompanying drawings, wherein:

Figure 1 is a perspective view of one of said nut constructions;

Figure 2 is a sectional elevation of the same shown screwed on a bolt.

The embodiment of the invention comprises a spring plate I having a marginal portion la at one edge secured, by brazing, welding, riveting or other methods, flat against a corresponding marginal portion of one end surface of a nut 2 close to one of the facets thereof. From this region of securement the plate I is, as clearly shown, first inclined away from, and then, at lb, turned parallel to, the said end surface of the nut, and said plate then turns back through 180 to be again parallel at lc to the said end surface. Thus said plate I comprises two parts lb and lo both parallel to the end surface of the nut, the part lb spaced a convenient distance from said end surface and the part lc spaced a still further convenient distance from the part lb. These two parallel parts lb and lo are formed with holes coaxial with the tapped hole in the nut, and thus, when the nut is screwed on the bolt, the latter passes through these two holes.

The two holes in the portions lb and to may be tapped to fit the screw threads of a bolt t (Figure 2), the arrangement being such that the screw threads of the said two holes are out of phase or lead with each other and with the screw threads of the nut, and thus the bolt in screwing into the two holes strains the portion lb of the plate from its normal position relative to the nut and also strains the portion lc from its normal position relative to the portion lb. This causes the threads of the two holes to drag frictionally on the thread of the bolt and prevents the nut from becoming unscrewed accidentally.

Alternatively the whole plate I may be of semisoft material with the holes in the portions ib and le so small that the bolt 4 will cut into the edges of said holes and form screw threads therein. This action would automatically strain the two portions lb and lo from their normal positions, and a friction drag wouldbe produced as before as shown in Figure 2.

The structure shown could be modified by increasing the number of parallel portions having holes for applying a friction drag. Thus the plate could be turned back a third time parallel to the end surface of the nut so that it would have three holes for the bolt, or indeed it could be turned back any number of times and have any number of holes.

In any of the above arrangements the plate is or" course shaped so that, in plan, it lies within the geometrical confines of the nut, and therefore does not interfere with the use of a wrench.

What we claim and desire to secure by Letters Patent is:

In a nut arranged with wrench engaging flats, a plate of resilient material folded upon itself with the folded portions disposed in parallel spaced relation and having axially alined threaded openings therein and of a cross sectional area to come within the flats of the nut, the free marginal portion of one folded plate portion being offset and the plate fixed at said ofiset portion to an end face of the nut with the plate portion from which it is offset spaced from said end of the nut and the plate openings being coaxially of the nut opening, and the screw threads of the threaded openings in the folded portions being out of phase with the screw threads of the nut and the spacing of the folded plate portion having the offset portion relative to the nut imparting additional friction effect to said folded plate portion.

RONALD D. KING. NORMAN F. WOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,222,460 Crowley Nov. 19, 1940 2,281,056 Tinnerman Apr. 28, 1942 1,893,067 Arenz Jan. 3, 1933 1,126,225 Judick Jan. 26, 1915 1,039,017 Bonness Sept. 17, 1912 2,367,259 Beach Jan. 16, 1945 678,629 Smith July 16, 1901 FOREIGN PATENTS Number Country Date 228,002 Great Britain Jan. 29, 1925 286,120 Great Britain Mar. 1, 1928 122,361 Austria Apr. 25, 1931 326,050 Great Britain Mar. 6, 1930 10,597 Great Britain June 11, 1900 

